Nested layout with valign-items="center" option. According to the CSS comment - nested layout has reset all defaults. Everything stays the same except for padding getting zeroed out.

Bolt layout item ISN'T vertically centerd, because lives in nested layout, where options are reset.
Tall item (The height of the layout items will not match. Some more text to make this taller. Lorem ipsum dolor sit amet consectetur adipisicing elit. Nulla tenetur natus dolore recusandae incidunt odio quasi reiciendis fugiat nihil quod? Assumenda culpa, cupiditate debitis ipsum excepturi tempora similique eum saepe! Lorem ipsum dolor sit amet consectetur adipisicing elit. Nulla tenetur natus dolore recusandae incidunt odio quasi reiciendis fugiat nihil quod? Assumenda culpa, cupiditate debitis ipsum excepturi tempora similique eum saepe!)
Bolt layout item is vertically centerd, because lives in first level layout with valign-items="center" option.